DIY gas refrigerator: the principle of the propane refrigerator + an example of assembly homemade

A fairly long history of the development of refrigeration is marked by the appearance of various types of household refrigerators. Among the existing structures, you can find a household absorption apparatus - a gas refrigerator.

Models of gas refrigerators are made both stationary and mobile. Their relatively simple design does not exclude the possibility of creating a device with their own hands. To make a gas refrigerator, you need to study its structure and principle of operation, agree?

The article describes in detail the design of the propane unit and the technical cooling cycle, as well as step-by-step instructions for assembling and remaking various modifications of gas refrigerators.

Propane refrigerator device

The absorption principle of operation is the basis of refrigeration technology that could work on propane.

Considering the gas refrigerator and the principle of its operation, it should be emphasized: in the absorption refrigerator, propane is given the modest function of a gas heater. The main components of the absorption process in the construction of household refrigerators are usually ammonia and water.

This is how the back wall of the absorption refrigerator looks. This is one of those old models of devices that are suitable for modernization - conversion to gas fuel instead of electric energy

Ammonia acts as a refrigerant, and water acts as an absorber.

The simplified gas model contains the following process modules:

1. Gas heating module.
2. Generator (more precisely - a boiler).
3. Capacitor.
4. Absorber (absorber).
5. Evaporator.

The gas heater heats the contents of the generator. The generator module is designed to produce vaporous ammonia and supply a weak ammonia solution to the absorber region.

The condenser module is used to cool ammonia vapor to a condensation temperature. A module called an “absorber” serves as an ammonia absorber.The gas cooler evaporator serves as a cold generator.

The principle of the gas refrigerator

The technological cooling cycle begins with the heating of a concentrated aqueous ammonia solution by a gas burner. Due to the lower boiling point of ammonia, this substance boils faster than water. The process of formation of concentrated refrigerant vapor, which enters the condenser, begins.

Here, the ammonia vapor condenses, and liquid ammonia rushes to the evaporator, where it boils due to the selection of heat from the products, forming a vapor-liquid mixture.

Block diagram showing the principle of operation of the absorption cooling apparatus. Here, a gas burner is used as a generator heater. However, in fact, the heater can be of almost any type (+)

The absorption refrigerator circuit also provides for the operation of the device, which is called the “reflux condenser”. This module is installed at the outlet of the boiler and is designed to produce a weak aqueous ammonia solution during the partial condensation of saturated vapors.

This weak solution is collected in an absorber. A saturated vapor-liquid ammonia mixture from the evaporator is sent there, where it is absorbed. Next, the cycle repeats.

Absorption refrigerator, prepared for modernization. A protective metal panel was dismantled, a heat insulator (a layer of mineral wool) was removed, and an electric heater was removed. There was only a sleeve on the siphon tube

Most absorption household refrigerators are equipped with electric heaters. For example, from such models refrigerators can be noted "Sadko", "Frost" other.

But it’s perfectly acceptable to replace an electric heater with any other heat source, including a propane burner, a heating radiator, and even chimney smoke.

Therefore, it is theoretically quite acceptable to use the noted models of absorption technology for the creation of a gas fridge, which operates in a constant mode, with one’s hands.

How to make a gas refrigerator

A relatively simple method of manufacturing a gas refrigerator, as already noted, is seen as the use of an exhausted absorption apparatus as the basis. To bring to mind the same Sadko or Morozko model, it is enough to exclude the electric heaters installed in the system from the design.

Instead of dismantled heating elements, it will be necessary to introduce gas heating by installing a heat exchanger and a propane burner in the design.

The theoretically feasible idea of ​​gasification of an absorption apparatus previously operating from heating with an electric heater. This is how the direct connection of a gas burner (+) is seen

The model of the “Morozko” absorption refrigerator of the fourth release of the ASh-30 series is suited to create a mobile device. Case dimensions of this design are 450 * 400 * 405 mm, weight no more than 15 kg.

The temperature of the freezer during construction at full power may well reach 10-12 ° C with a minus sign. It was not for nothing that among the craftsmen-designers the idea was born to remake electric heating, replacing it with a propane heating pad.

However, the idea of ​​a gas refrigerator is dubious, and there are a number of reasons to confirm this. So, the absorption process requires almost twice as much time to generate cold than a conventional compression refrigerator.

From the point of view of economy, the design does not seem to be entirely rational, given how much gas it will take to get 1 ° C below zero for a home-made version. Nevertheless, the design interest regarding the possibility of implementing the idea is quite high.

Step-by-step process of remaking "Sadko"

The electric heating elements of the Sadko refrigerator are located on the siphon tube. This structural element (siphon) is located at the bottom of the rear wall of the apparatus.The siphon area is covered by a metal casing, under which there is a layer of heat insulator (mineral wool).

The process of opening the protective metal panel on the rear wall of the absorption refrigerator is shown here. As you can see, under the panel and the insulator layer there is an electric heater, which needs to be removed

Initially, an amateur designer will need to do the following:

1. Place the refrigerator in a convenient place for work.
2. Remove the protective cover on the rear wall.
3. Remove thermal insulation material.
4. Remove the heating elements from the siphon tube.

It should be borne in mind that do-it-yourself modification is associated with some risk. The absorption refrigerator system is filled with ammonia and hydrogen under pressure up to 2 atm. Careless dismantling of system parts and electric heaters can lead to depressurization of the system, which is hazardous to health. Care must be taken.

The next step of the amateur designer is to install a heating system operating on propane. That is, it is necessary to mount a module in the area of ​​the siphon tube, which would be used for heating as a result of gas combustion. It is unacceptable to heat the tube with an open flame.

So, you need to make a heat exchanger. It can be, for example, a massive bar of copper, inside which is built gas-burner.

An option for manufacturing heat exchange modules for the internal placement of a gas burner. Such a module is fixed tightly to the siphon tube of the refrigerator instead of the dismantled electric heater

The manufacture of a gas heating system without fail provides for the organization of a complex of protection against overheating. The operating temperature range for heating the siphon of the Sadko refrigerator is 50 - 175 ° C. Based on these values, it is necessary to consider the scheme of switching on and off the gas supply during heating.

For a circuit with electric heaters in absorption models, it is used refrigerator thermostat T-120 series. But this device regulates the operation of heaters taking into account the temperature of the evaporator.

The gas burner flame regulator, which can be implemented in the design of the gas heating module. This is just one of several automation devices that you need to equip a gas refrigerator (+)

A gas burner along with an automatic control device is a slightly different system. If a propane refrigerator is made taking into account long-term use, the automation will have to be made full.

That is, for example, to control not only the heating temperature of the heat exchanger, but also to control the flame and monitor the gas pressure. We must not forget about the system fuse.

Homemade assembly examples

It was not possible to find examples of home-made designs of gas absorption refrigerators that would be noted by long-term operation. There are only experimental options, often begun, but not brought to completion.

There are also examples of assembly when a gas fridge was assembled by one’s own hands using a simplified technique.

One of the successful self-made propane refrigerator designs. Such "homemade" products on the Internet can be found in sufficient quantities

With a simplified version of the assembly used propane tankthe outlet of which was connected by a hose directly to a direct-acting burner. The burner was fixed on the chassis of the absorption refrigerator, and the working nozzle was sent directly to the siphon tube.

Burner ignition was done manually. Also, without any automation, purely by the “touch test” method, the siphon heating temperature was controlled.

The results are disappointing. During the operation of the manual heating gas installation for 12 hours, the maximum temperature of the lower threshold was obtained inside the freezer, not lower than + 3 ° С.

Thus, tests of a propane absorption refrigerator made by hand according to a simplified scheme showed an extremely low efficiency of the gas apparatus. Moreover, judging by the gas consumption, this option for producing cold ("Sadko-G") is unreasonably costly.

Homemade alternative

The meaning of assembling the gas structure is also lost because there are practically no old factory structures of this kind in the domestic version. Gas refrigeration equipment with an absorber (Russian-made) is basically an industrial installation, large-sized, heavy, equipped with sophisticated gas equipment.

An example of an industrial absorption gas plant. With a relatively small gas consumption (in industrial accounting), this absorption cooler shows high efficiency

Therefore, an alternative for homemade gas refrigeration equipment is considered more attractive. These are modern mobile compact cooling systems from a series of thermal containers and similar developments. Any of such systems closes the need for cold, which burdens outdoor enthusiasts.

It is for the purpose of cooling and storing products in the conditions of outdoor recreation that people try to assemble gas refrigerators with their own hands. The range of modern mobile refrigeration equipment is huge

The price of the devices is quite suitable. Most likely, buying, say, a brand refrigerator Comfort, will cost several times less than the cost of upgrading the old absorption system.

Moreover, the technical characteristics of modern compact refrigeration equipment actually comparable to the same parameters "Sadko". And the temperature range looks more attractive (up to -18ºС).

More than a successful alternative to home-made gas refrigerator designs. Convenient, mobile, compact Waeco-Dometic Combicool, operating from three different heat sources

Finally, it is possible to buy imported industrial refrigerators that actually operate on propane. A good example is a universal device of a German manufacturer, manufactured under the brand name Waeco-dometic combicool.

The design of the mobile refrigerator provides cold during operation from one of the three energy sources, including a gas cylinder.

Conclusions and useful video on the topic

Advantages and disadvantages of a mobile refrigerator that can run on both electricity and gas:

A brief video review of the Dometik car refrigerator:

Conclusions from the whole history with the construction of "free" in all respects refrigeration equipment follow unambiguous. The only reason for building a gas refrigerator on your own is the desire to do something yourself.

Often the pleasure of one’s own success overrides any global innovation. However, modern factory models are more reliable and safer.

Have experience creating a gas refrigerator? Or do you use a commercial absorption type unit? Please share your opinion and leave comments. The contact form is located in the lower block.